One knowledgeable in the art of occupant-propelled vehicles will be readily aware that there is a deficiency in the prior art relative to the steering of occupant-propelled vehicles such as wheel chairs. The problem is particularly prevalent with chairs propelled by a single-arm force receiver, such as a drive lever. Steering with such prior art devices has proven mechanically and functionally complex, commonly presenting users with an ergonomically unfriendly steering apparatus.
For example, in some devices, a user is required to rotate a control grip about an axis that is generally perpendicular to the user's arm to rotate a caster wheel via a chain, joint, or lever connection. In some steering mechanisms of this type, the grip communicates along its axis of rotation. In others, the grip is perpendicular to its axis of rotation. In both arrangements, many find the required contortion of one's wrist and arm while expending a driving force upon a force-receiving lever difficult and uncomfortable. Furthermore, the steering direction inadvertently may be affected by one's exertion of a propelling force.
Similarly inefficient and uncomfortable are prior art steering devices that require a user to rotate a shovel type handle. Other steering systems include complex multi-gear force transmission arrangements, and prior art systems commonly do not provide a means for disengaging the steering controls to allow free motion of the caster as would be useful when the chair is to be pushed by a second person.
In total, one sees that prior art occupant-propelled vehicle steering arrangements are undesirably complex and uncomfortable to operate. Consequently, it would be advantageous if one were to provide a steering arrangement that is simple, effective, and durable while being comfortable to operate.